SpaceX hits two milestones in plan for low-latency satellite broadband

SpaceX got good news from the FCC and will launch two demo satellites Saturday.

SpaceX's satellite broadband plans are getting closer to reality. The company is about to launch two demonstration satellites, and it is on track to get the Federal Communications Commission's permission to offer satellite Internet service in the US.

Neither development is surprising, but they're both necessary steps for SpaceX to enter the satellite broadband market. SpaceX is one of several companies planning low-Earth orbit satellite broadband networks that could offer much higher speeds and much lower latency than existing satellite Internet services.

Further Reading

Today, FCC Chairman Ajit Pai proposed approving SpaceX's application "to provide broadband services using satellite technologies in the United States and on a global basis," a commission announcement said. SpaceX would be the fourth company to receive such an approval from the FCC, after OneWeb, Space Norway, and Telesat. "These approvals are the first of their kind for a new generation of large, non-geostationary satellite orbit, fixed-satellite service systems, and the Commission continues to process other, similar requests," the FCC said today.

SpaceX's application has undergone "careful review" by the FCC's satellite engineering experts, according to Pai. "If adopted, it would be the first approval given to an American-based company to provide broadband services using a new generation of low-Earth orbit satellite technologies," Pai said.

Falcon 9 has two demo satellites

Separately, CNET reported yesterday that SpaceX's Falcon 9 launch on Saturday will include "[t]he first pair of demonstration satellites for the company's 'Starlink' service."

The demonstration launch is confirmed in SpaceX's FCC filings. One SpaceX filing this month mentions that a secondary payload on Saturday's Falcon 9 launch will include "two experimental non-geostationary orbit satellites, Microsat-2a and -2b."

Those are the two satellites that SpaceX previously said would be used in its first phase of broadband testing.

Further Reading

"These are experimental engineering verification vehicles that will enable the company to assess the satellite bus and related subsystems, as well as the space-based and ground-based phased array technologies," SpaceX told the FCC.

SpaceX originally told the FCC that it might launch these test satellites by the end of 2017, so the launch is slightly later than that optimistic estimate. Longer-term, SpaceX has said that it might begin the launch of operational satellites as early as 2019. Further satellites will be launched in phases, with SpaceX intending to reach full capacity with 4,425 satellites in 2024.

Gigabit speeds, low latency

SpaceX has said it will offer speeds of up to a gigabit per second, with latencies between 25ms and 35ms. Those latencies would make SpaceX's service comparable to cable and fiber. Today's satellite broadband services use satellites in much higher orbits and thus have latencies of 600ms or more, according to FCC measurements.

The demonstration satellites will orbit at 511km, although the operational satellites are planned to orbit at altitudes ranging from 1,110km to 1,325km. By contrast, the existing HughesNet satellite network has an altitude of about 35,400km, making for a much longer round-trip time than ground-based networks.

We asked SpaceX for an update on its satellite broadband plans today, but the company declined to comment.

OneWeb was the first company to seek FCC approval to enter the US broadband market with low-Earth orbit satellites and received approval in June 2017. OneWeb wants to offer service in Alaska as early as 2019. Boeing is also planning to offer satellite broadband.

Pai praised SpaceX and other companies for using "innovative technologies" to improve broadband access. "Satellite technology can help reach Americans who live in rural or hard-to-serve places where fiber optic cables and cell towers do not reach," Pai said. "And it can offer more competition where terrestrial Internet access is already available."

Promoted Comments

This will be absolutely fantastic for developing nations. Being able to bypass fiber-optic backbones for consumer connections will be a huge benefit. Imagine how many rural villages will be able to set up a couple of receivers to share among the residents.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

You need a lot more satellites to cover the same amount of area if you go with a lower orbit vs higher one. This increases speed and lowers latency, but immensely increases cost as you need to make, maintain and launch more satellites.

Now if you are a company that just so happens to sell the cheapest commercial launches and can stack like 10 satellites per launch, then all of a sudden it becomes much more feasible.

This will be absolutely fantastic for developing nations. Being able to bypass fiber-optic backbones for consumer connections will be a huge benefit. Imagine how many rural villages will be able to set up a couple of receivers to share among the residents.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

They are in geostationary orbit.

Allows them to use fewer satellites for communications.

Plus, it would cost them a lot more to put up a network similar to the GPS network.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

You need a lot more satellites to cover the same amount of area if you go with a lower orbit vs higher one. This increases speed and lowers latency, but immensely increases cost as you need to make, maintain and launch more satellites.

Now if you are a company that just so happens to sell the cheapest commercial launches and can stack like 10 satellites per launch, then all of a sudden it becomes much more feasible.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

I think it's because it requires more satellites?

Yep. You only need a few dozen satellites if they are that far up. LEO orbit will require thousands of them, which is the SpaceX plan.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

Because Hughes satellites are geostationary, meaning you point your dish at one satellite (satellite orbit speed is related to how far away from the earth a satellite is, 35,000 km and the orbit is 24 hours, i.e. GEO). This is how satellite TV works also (although sometimes one dish is catching multiple satellites near each other).

Having the satellites at LEO or MEO means that they will move across the sky constantly, meaning that you're not just pointing your dish at a single target. I.e. it will work more like the satellite phones and GPS do.

As for why noone else has done it, I would say that because the technology and bandwidth is hard to do, especially with a small satellite. I wonder how many users a system like this could support?

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

I think it's because it requires more satellites?

More satellites, yes. But also technical hurdles of controlling so many of them. At that altitude, they can't do geostationary orbits (not fast enough to stay in orbit), which means, if this works (and by all accounts, it should), SpaceX can be the proud owners of the first global internet infrastructure. One network, under the auspices of a single entity that is actively driving innovation, covering the entire planet.

It'll be interesting to learn about the capabilities of inter-satellite communication for this network, and to learn about how they'll be communicating with ground stations. Figuring out how to efficiently route traffic from one satellite to the next before sending the packets to the ground will be an interesting problem to solve.

This will be absolutely fantastic for developing nations. Being able to bypass fiber-optic backbones for consumer connections will be a huge benefit. Imagine how many rural villages will be able to set up a couple of receivers to share among the residents.

Or the ability to sidestep restrictive government bodies that control the "tubes". Imagine a whole new era of "Radio Free Europe"

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

Satellites orbiting at 36K Km orbit at the same rate as Earth is spinning so they remain over the same longitude. This is called a geosynchronous orbit. If such a satellite orbits directly over the equator then they appear to remain stationary in the sky. This is a geostationary orbit. This is why the little home satellite TV dishes are placed stationary pointing at the sky. Geostationary orbits are perfect for comm satellites but they do cause large latency due to speed of light being finite. Such satellites, being so high, can cover nearly an entire hemisphere with their signal.

Low earth orbit requires:-more satellites to guarantee uninterrupted coverage as they continue to pass overhead and drop below the horizon, and their ground footprint is much smaller due to lower altitude. But the latency is much better making this a better choice for internet access.-tracking dish antennas to sweep the sky as the satellite is passing overheard-OR an omni-directional antenna which does not require precise pointing, which is what SpaceX will be doing. But this requires better signal or better signal processing because the antenna gain is not nearly as good.

Edit: no 1 thing to understand here is that in low earth orbit the Earth gravity is well over 90% of surface gravity. It's almost the same. Satellites don't just hover up there. They can't. They'd need forever-thrusters (impossible) or they'd fall back down immediately. The satellites remain in orbit because their horizontal speed (imparted by the launch rocket) summed with the pull of gravity results in a velocity vector which is pointing above the horizon. That's what an orbit is. The satellites are perpetually free-falling toward the horizon and their path never intersects with the ground. We've chosen such a path on purpose when launching the rocket. So satellites are moving. Fast. They have to. When they are at 36K Km they are moving at the same rate as Earth is spinning, which makes them appear stationary to a ground observer when their orbit is over the equator. (An orbit anywhere else besides directly above the equator and the satellite would appear to oscillate up and down in the sky.) The speed of a satellite is proportional to the orbital altitude. Below 36K Km they are orbiting faster than Earth spin, and above 36 Km slower and from the ground it makes it appear as if satellites are going backwards.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

Satellites orbiting at 36K Km orbit at the same rate as Earth is spinning so they remain over the same longitude. This is called a geosynchronous orbit. If such a satellite orbits directly over the equator then they appear to remain stationary in the sky. This is a geostationary orbit. This is why the little home satellite TV dishes are placed stationary pointing at the sky. Geostationary orbits are perfect for comm satellites but they do cause large latency due to speed of light being finite. Such satellites, being so high, can cover nearly an entire hemisphere with their signal.

Low earth orbit requires:-more satellites to guarantee uninterrupted coverage as they continue to pass overhead and drop below the horizon, and their ground footprint is much smaller due to lower altitude. But the latency is much better making this a better choice for internet access.-tracking dish antennas to sweep the sky as the satellite is passing overheard-OR an omni-directional antenna which does not require precise pointing, which is what SpaceX will be doing. But this requires better signal or better signal processing because the antenna gain is not nearly as good.

What I'm curious to know is the spectrum range and antenna structure they're intending to use and if it will be more weather-tolerant than current systems. This satellite web connection won't be very practical in many places if it gets spotty at the first sign of rain like conventional directional antennae.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

You need a lot more satellites to cover the same amount of area if you go with a lower orbit vs higher one. This increases speed and lowers latency, but immensely increases cost as you need to make, maintain and launch more satellites.

Now if you are a company that just so happens to sell the cheapest commercial launches and can stack like 10 satellites per launch, then all of a sudden it becomes much more feasible.

Plus the sats won't last as long with the higher drag they are exposed to. SpaceX is targeting a 5-7 year lifespan vs a 15-20 year lifespan for GSO comsats.

So you are going to need a lot of launches to build it and a lot of launches to continually replace sats. Good thing SpaceX knows something about low cost high cadence launches.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

Satellites orbiting at 36K Km orbit at the same rate as Earth is spinning so they remain over the same longitude. This is called a geosynchronous orbit. If such a satellite orbits directly over the equator then they appear to remain stationary in the sky. This is a geostationary orbit. This is why the little home satellite TV dishes are placed stationary pointing at the sky. Geostationary orbits are perfect for comm satellites but they do cause large latency due to speed of light being finite. Such satellites, being so high, can cover nearly an entire hemisphere with their signal.

Low earth orbit requires:-more satellites to guarantee uninterrupted coverage as they continue to pass overhead and drop below the horizon, and their ground footprint is much smaller due to lower altitude. But the latency is much better making this a better choice for internet access.-tracking dish antennas to sweep the sky as the satellite is passing overheard-OR an omni-directional antenna which does not require precise pointing, which is what SpaceX will be doing. But this requires better signal or better signal processing because the antenna gain is not nearly as good.

What I'm curious to know is the spectrum range and antenna structure they're intending to use and if it will be more weather-tolerant than current systems. This satellite web connection won't be very practical in many places if it gets spotty at the first sign of rain like conventional directional antennae.

Not sure I can find it again, but I vague recall that they don't expect weather to be much of an issue.

This will be absolutely fantastic for developing nations. Being able to bypass fiber-optic backbones for consumer connections will be a huge benefit. Imagine how many rural villages will be able to set up a couple of receivers to share among the residents.

I agree there’s a real potential for that kind of development but SpaceX still has to recoup costs and turn a profit, it can’t provide the service for free - and rural villages in developing nations are not known to be centers of revenue generation. Nevertheless, it could be a good deal cheaper for them than installing fiber optic cable.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

You need a lot more satellites to cover the same amount of area if you go with a lower orbit vs higher one. This increases speed and lowers latency, but immensely increases cost as you need to make, maintain and launch more satellites.

Now if you are a company that just so happens to sell the cheapest commercial launches and can stack like 10 satellites per launch, then all of a sudden it becomes much more feasible.

Plus the sats won't last as long with the higher drag they are exposed to. SpaceX is targeting a 7 year lifespan vs a 15-20 year lifespan for GSO comsats.

So you are going to need a lot of launches to build it and a lot of launches to continually replace sats. Good thing SpaceX knows something about low cost high cadence launches.

At the risk of sounding dumb: Why do the Hughes sats sit so high in orbit? What kind of issues can we expect to run into with low orbit communication sats like SpaceX is planning? I know low orbit is ideal for latency, but there has to be a reason nobody else has done it.

Satellites orbiting at 36K Km orbit at the same rate as Earth is spinning so they remain over the same longitude. This is called a geosynchronous orbit. If such a satellite orbits directly over the equator then they appear to remain stationary in the sky. This is a geostationary orbit. This is why the little home satellite TV dishes are placed stationary pointing at the sky. Geostationary orbits are perfect for comm satellites but they do cause large latency due to speed of light being finite. Such satellites, being so high, can cover nearly an entire hemisphere with their signal.

Low earth orbit requires:-more satellites to guarantee uninterrupted coverage as they continue to pass overhead and drop below the horizon, and their ground footprint is much smaller due to lower altitude. But the latency is much better making this a better choice for internet access.-tracking dish antennas to sweep the sky as the satellite is passing overheard-OR an omni-directional antenna which does not require precise pointing, which is what SpaceX will be doing. But this requires better signal or better signal processing because the antenna gain is not nearly as good.

What I'm curious to know is the spectrum range and antenna structure they're intending to use and if it will be more weather-tolerant than current systems. This satellite web connection won't be very practical in many places if it gets spotty at the first sign of rain like conventional directional antennae.

The phased array and shorter distances (allowing higher link power) should make it better than conventional sat but it is still going to have rain fade. Water is kinda an ass in that it attenuates quite a large number of frequency ranges.